A hierarchy of faithful set creation in pure OODB's

Abstract

In a general, pure object-based setting, we consider the issue of creating objects which faithfully represent sets. Faithfulness means that no duplicates are generated, and is therefore an important notion, not only from a data modeling perspective, but also for efficiency reasons. Our main result is that, modulo one exception, the ability to create objects which faithfully represent sets whose cardinality is bounded by a fixed constant m, is strictly weaker than that for sets with cardinality bounded by m + 1. We thus establish a strictly increasing hierarchy.